The prior art is replete with coupling devices which may be employed for power transmission, both permanently engaged and also releasably engageable. Likewise, there are numerous "couplings" in the fastener art. A blade or a Phillips Screwdriver engaging and rotating a screw is also a "coupling" within the meaning of this application. It is one of the objects of this invention to provide a rotatable coupling applicable to all phases of transmission of rotary motion.
One of the problems encountered with disengageable rotatable couplings is the necessity of aligning the driving member with the driven member prior to actually rotating the driver. For example, the common lag bolt or other fastener having a hexagonal head is frequently driven by a driving socket having a mating hexagonal cavity. Often, the socket is operated by a ratcheted socket wrench. However, before actually rotating the hexagonal socket, its corners must be aligned precisely with the corners of the hexagonal head of the bolt in order to slide the socket over the head.
Similarly, the axis of rotation of a driving socket must also be substantially aligned with the axis of rotation of the driven member. Again, using the example of the lag bolt, the socket will not fit over the head of the bolt if their axes are not aligned. Not only must the alignment be such that the axes are co-linear, i.e., not displaced laterally, even though parallel, but the axes must also not be angularly misaligned.
It is, accordingly, another object of this invention to provide a coupling member wherein the driving and driven members may be slightly out of axial alignment, both in displacement and angularity, and still be capable of attaining mating driving engagement while aligning themselves.
It is also an object of this invention that the rotatable coupling have utility as flexible couplings rotary transfer joints, torque transfer joints and specialty fasteners, just to mention a few.
With the versatility contemplated for the subject invention, it could be incorporated into a robotic gripper for torque transfer due to its unique self-aligning nature. It would also have utility in tool changing linkage. It would allow robotic installation of fasteners since the driver and driven member are self-aligning.
It is contemplated that the coupling include male and female components, the male being essentially a bit with external lobes and the female having internal receiving chambers formed to receive the lobes. It is intended that these members be symmetrical to effect driving in both a clockwise and counter-clockwise direction.
It is intended that the bit employ conical or wedge-shaped entry surfaces with mating conical or wedge-shaped surfaces on the female member so that the cones or wedges slide upon one other, even though they are initially out of alignment.